1. Field of the Invention
The invention relates to surgical instruments and, more particularly, to a combination instrument for atraumatic grasping, bipolar coagulation by means of high frequency current and cutting out human or animal tissue. The instrument is particularly intended for the purpose of making the fallopian tubes in a woman impassable by means of an abdominal specular operation, hereinbelow called laparoscopical tube sterilization.
2. Description of the Prior Art
Surgical operations have long been performed in human medicine for the purpose of sterilization, for instance, to make impassable the fallopian tubes in women or the sperm ducts in men. First used for this purpose were surgical methods in open surgery which made the organs impassable by blocking them by means of a thread and subsequently sharply cutting them.
As early as 1937, Anderson (USA) utilized the tissue destroying effect of high frequency current for laparoscopical tube sterilization in gynecology. This technique was further developed after appropriate instruments were designed, for instance, by SEMM (Germany), the companies Karl Storz GmbH and Richard Wolf GmbH. The technique is still used today for laparoscopical tube sterilization.
Two methods of coagulating tissue by means of high frequency current are used today. They are (1) the unipolar high frequency method and (2) the bipolar high frequency method.
In the unipolar high frequency method, a neutral electrode, usually attached to the thigh of the patient, forms one pole. A functional device at the laparoscopical instrument forms the other pole for the high frequency current (for instance, unipolar hooked scissors according to SEMM).
In the bipolar high frequency method, wherein both electrodes are opposite one another in the area of the functional unit of the surgical instrument (for instance, bipolar grasping forceps, Karl Storz GmbH), the high frequency current is conducted only through the tissue grasped by the functional units.
In order to perform a laparoscopical tube sterilization by coagulation with high frequency current and to remove tissue, it is presently necessary, after applying a pneumoperitoneum and inserting an optical instrument, first to grasp the tube, for instance, with the bipolar grasping forceps (Richard Wolf GmbH) and to coagulate the tube, then to remove this instrument, insert a cutting instrument, for instance, the unipolar hook-type cutter according to Frangenheim, to cut out a portion of the tube in the coagulated area, and, after another instrument change, to remove the cut tube portion from the abdominal cavity by means of grasping forceps.
The use of unipolar high frequency current for tube coagulation should be considered obsolete today because the current may cause uncontrolled burning at completely different portions of tissue which were not even touched by the surgeon.
When using the bipolar high frequency method for the coagulation of tubes, the instruments available today make it necessary, after insertion of a bipolar grasping forceps and subsequent coagulation of a tube portion, to again remove the forceps, insert a cutting device, and to cut the tube in the area which previously was coagulated. If, in addition, a tube section is to be removed, several cuts must be made which is particularly difficult with cuts at an angle of 90.degree. to the guide sleeve of the cutting instrument, because the cutting device is rigid relative to the guide sleeve. This has the serious disadvantage that these manipulations result in cuts in non-coagulated areas and cause dangerous bleeding. In addition, the instrument must be changed for a third time in order to remove the cut out tissue from the abdominal cavity.
Since the bipolar grasping forceps used today have an electrode width of only 5 to 6 mm, the tube is grasped and coagulated several times, so that sometimes the tube is unnecessarily destroyed over its entire length.
In addition, coagulation frequently takes place far beyond the tubes in the appendages because these instruments have no stops against the electrodes and, consequently, the tissue, in this case the tubes, may reach much too deeply between the grasping units of the bipolar forceps. If tissue is successfully removed in spite of these difficulties, the removed tissue is completely destroyed by the coagulation and can be histologically identified only with difficulty or not at all. Although tissue removal for histological identification is internationally demanded, it is usually not performed because (1) the surgical risk is substantially increased, and (2) a proper histological identification is doubtful.